The man heaved deeply half a dozen times, shook, then slumped in his wheelchair.

The images, broadcast worldwide, prompted claims that the Pope had either performed an exorcism or a prayer to free the man from the devil.

Pope Francis, with his background in Latin American and Jesuit spirituality, is known to frequently refer to the devil, leading some to claim he has a fascination with Satan.

The Vatican, however, insisted he "didn't intend to perform any exorcism. But as he often does for the sick or suffering, he simply intended to pray for someone who was suffering who was presented to him".

Exorcisms in New Zealand are rare, but they do happen - and Catholic Education Office chief executive Pat Lynch said canon law made it obligatory for a bishop to have someone able to perform an exorcism.

"These things, they are not in the realm of fantasy," he said.

He remembered a house, near where he lived in Auckland in the 1970s, where "some sort of black magic was taking place".

"People were getting in touch with the Underworld."

The story was that a one-metre hole would open up in the side of a wall, leaving scorch marks around it.

While parts of the story may have been embellished, a priest with exorcism credentials was brought in to perform the ritual as described in the canon for exorcising spirits.

The ritual apparently worked, he said.

"I have no reason to disbelieve it."

Anglican vicar Michael Hewat, of the West Hamilton parish, said he saw his job as doing what Jesus did - including exorcism.

"The truth is some clergy either don't believe in demonic forces or they may feel lacking in confidence," he said.

Manifestations of a demonic force ranged from people hissing like snakes, to people with supernatural strength or "super-human evilness".